//Purpose:
//  Explore how to minimize space taken by struct of
//  optionals.
//Reference:
//
//  http://article.gmane.org/gmane.comp.lib.boost.devel/209212
//
#include <boost/optional.hpp>
#include <boost/type_traits/alignment_of.hpp>
#include <iostream>

struct A {
    int a;
    double b;
    double c;
    std::string d;
};

struct B {
    boost::optional< int > a;
    boost::optional< double > b;
    boost::optional< double > c;
    boost::optional< std::string > d;
}; 

struct Atags {
    int a;
      bool ta;
    double b;
      bool tb;
    double c;
      bool tc;
    std::string d;
      bool td;
}; 

struct tagsA {
      bool ta;
    int a;
      bool tb;
    double b;
      bool tc;
    double c;
      bool td;
    std::string d;
}; 

struct A_bools {
    int a;
    double b;
    double c;
    std::string d;
    
    bool ta;
    bool tb;
    bool tc;
    bool td;
    
}; 

struct bools{

    bool ta;
    bool tb;
    bool tc;
    bool td;
};

struct bools_A {
    bool ta;
    bool tb;
    bool tc;
    bool td;
    //bool te; //uncomment this, and sizeof(bools_A) jumps by alignment_of<A>::value.
    
    int a;
    double b;
    double c;
    std::string d;
    
}; 

int main(void)
{
    std::cout<<"alignment_of<A>::value="<<boost::alignment_of<A>::value<<"\n";
    std::cout<<"sizeof(A)="<<sizeof(A)<<"\n";
    std::cout<<"sizeof(B)="<<sizeof(B)<<"\n";
    std::cout<<"sizeof(Atags)="<<sizeof(Atags)<<"\n";
    std::cout<<"sizeof(tagsA)="<<sizeof(tagsA)<<"\n";
    std::cout<<"sizeof(A_bools)="<<sizeof(A_bools)<<"\n";
    std::cout<<"sizeof(bools_A)="<<sizeof(bools_A)<<"\n";
    std::cout<<"sizeof(bools)="<<sizeof(bools)<<"\n";
    std::cout<<"sizeof(int)="<<sizeof(int)<<"\n";
    std::cout<<"alignment_of<bools>::value="<<boost::alignment_of<bools>::value<<"\n";
    return 0;
}